1. Field of the Invention
The present invention relates to an air intake device of an engine.
2. Description of the Related Art
A conventional structure includes an idle number-of-revolutions control device that is fitted to a throttle body and controls an idle number of revolutions of an engine to a target number of revolutions according to the state of the engine. For example, an idle number-of-revolutions control device disclosed in Japanese Unexamined Patent Publication No. 9-42119 has a water collection portion formed therein and can temporarily store dew condensed in the throttle body and water droplets from air cleaner piping in the water collection portion.
In the device disclosed in Japanese Unexamined Patent Publication No. 9-42119, the water collection portion is arranged on the downstream side of the idle number-of-revolutions control device. The idle number-of-revolutions control device has a valve body built in an air flow passage extending from an air cleaner, the valve body being operated by a proportion type solenoid. Thus, there is a possibility that moisture from the air cleaner will adhere to the valve body and will freeze up, and in that case, a problem is caused in that the idle number-of-revolutions control device will not smoothly operate.